The mortality rate for patients with Anorexia Nervosa is the highest of any psychiatric disease, and varies from six to twenty percent depending on the series. Death is often sudden and unexpected, and in this setting is almost certainly caused by abnormalities of cardiac rhythm. Review of the current literature, provides little assistance for clinicians responsible for managing such patients, in the identification of patients at risk for sudden death. This study is being proposed as a pilot or exploratory study aiming to identify risk factors which may be predictive of risk for sudden death. A larger, possibly multi-center collaborative study will be needed to more completely delineate such risk factors. Patients with Anorexia Nervosa seen at Children's Hospital at Stanford and Stanford Medical Center will comprise the patient population. Assessment of patients will take place at four times during the study period: 1) on admission to the study, 2) two weeks after admission, 3) when within 10% of target weight, 4) when at target weight. The presence of abnormalities of cardiac rhythm will be screened for by conventional 12 lead EKG, and by 24 hour Holter monitoring at each of the four study intervals. At each of the four study intervals, a history and physical examination of the cardiovascular system will be performed, routine serum electrolytes and serum magnesium ad serum calcium will be performed, measurement of QT interval, and echocardiogram assessing ventricular contractility, and ventricular size will be performed, and finally, oxygen consumption will be measured at rest, at the four study intervals. Type and frequency of cardiac dysrhythms will be described. Statistical analysis will be performed as follows: Two groups will be constructed, one with ventricular dysrhythmias noted on EKG or Holter monitoring, and the other group without dysrhythmias. Mean values of measured independent variables, such as cardiovascular vital signs, serum electrolyte values, assessment of cardiac contractility and ventricular chamber size, will be compared between the two groups by univariate analysis with students' t-test or Chi2 test. Multivariate analysis, including discriminate function analysis will be performed to determine the relative significance of factors associated with cardiac dysrhythmias.